To determine the aberration pattern of the cornea from its shape.
ID
Source
Brief title
Condition
- Anterior eye structural change, deposit and degeneration
Synonym
Research involving
Sponsors and support
Intervention
Outcome measures
Primary outcome
The main study parameters are the following Zernike polynomials for defocus
(z20), astigmatism (z2-2 and z22), coma (z3-1 and z31) and spherical aberration
(z40) for both the description of corneal shape and corneal wavefront.
Secondary outcome
None
Background summary
The optical quality of the human eye is pivotal for the quality of vision of
the subject - and thus for quality of life. Imperfections in the eye optics are
called aberrations and are measured with wavefront analysis. The optics of the
eye consists of the cornea and the crystalline lens. During a cataract
extraction, the crystalline lens is replaced by an intraocular lens (IOL). The
aberrations of the cornea can - theoretically - be compensated by the IOL. This
IOL should then be custom made. When measuring the aberrations of a subject,
one always measures the aberrations of the complete system (i.e. cornea +
lens). However, for predicting the aberrations after a cataract extraction it
is necessary to know the aberrations of the cornea alone. This requires a
thorough understanding of the relationship between the shape of the cornea and
the corresponding aberration pattern. We will determine this relationship by
measuring the shape of the cornea and the aberration pattern of the whole eye
in patients who already had a cataract extraction in the past. In these
patients, we know the optical properties of the lens (IOL). This relation can
then be used to predict the aberration pattern of future cataract-extraction
patients pre-surgery.
Study objective
To determine the aberration pattern of the cornea from its shape.
Study design
Cross-sectional study.
Study burden and risks
The measurements of both the corneal shape (by the Pentacam HR) and the
aberration pattern (by the WASCA) are harmless procedures that do not contain
any risk for the subject. Both instruments are already used for regular ocular
examinations and validated for use in the clinic.
The risks of the eye-drops of tropicamide are none, due to the fact that
subjects are pseudo-phakics; there is no risk of acute glaucoma. The mydriasis
of the eyedrops will cause a mild photophobia in one eye, which can be
minimised by wearing sunglasses.
In total the subjects will extent a regular visit to the UMCG by 30 minutes.
The subjects do not have a benefit to participating in the study, however the
results of the study will benefit future patients because the final aim of the
project is individualized IOL design aiming to reduce optical aberrations after
the cataract extraction. There is no risk of finding previously undiscovered
ocular diseases because all patients were thoroughly checked for other eye
diseases as part of the cataract extraction procedure.
Hanzeplein 1
Groningen 9700RB
NL
Hanzeplein 1
Groningen 9700RB
NL
Listed location countries
Age
Inclusion criteria
The inclusion criteria are that subjects are 18 years or above and underwent a successful cataract extraction and got an IOL implanted.
Exclusion criteria
Exclusion criteria are subjects with any history of ocular disease, other than the cataract extraction, and refractive surgery. Also the cataract extraction should have been successful without any complications.
Design
Recruitment
Followed up by the following (possibly more current) registration
No registrations found.
Other (possibly less up-to-date) registrations in this register
No registrations found.
In other registers
| Register | ID |
|---|---|
| CCMO | NL40670.042.12 |